Microtome



yMmh 24, 1931. H. N, OTT 1,797,694

MICROTOME Filed Aug. 29, 1929 5 Sheets-Sheet l Wil* l' y1 /N l/E/v fof?.

Marc-h 24, 1931.

H. N. OTT

MICROTOME 3 Sheets-Sheet 2 Filed Aug. 29, 1929 il@ @lim H. N. OTT

MICRoToME March 24, 1931.

Filed Aug. 29, 1929 5 Sheets-Sheet 3 ,5. N @www W Patented Mar. 24, 1931 HARVEY N. OTT, or Bussero, new Yoan, assienoafro sriincnarnns COMPANY, or

Y BUrrAno, new YORK i Application led August 29, 1929. Serial No. 389,189.

This invention relates-to improvements in microtoines for cutting thin slices or sections of objects or materials for use as specimens for microscopic study. f

Certain features of the invention relate to knife supporting and knife holding means used in connection with that type of microtomc having the .knife or cutting member mounted on a sliding'support.which is reciprocat'edbv hand for passing the knife across'the object to cut the slices therefrom` the latter being mounted in a holder Which isadvancedstep by step to bring` successive portions of the object into the cutting plane. Other features of the invention relate to means for supporting the, object, and these means are equally Well adapted for use on microtomes of the kind designated, or on the other types Well known in the art.

In some of the microtomes ofthe type above described the knife carriage is in the form of a block slidably mounted in a guide groove or Way, and is held in engagement therewith by its own Weight only. It has been found, however, that in cutting specimens of rel-altively tough or resistant character on such apparatus that the knife carriage has a tendency to ump or move upwardly away from vor out of contact with the guide or bearing surfaces of the ,guidevvay When the knife engages the object. This of coursemakes it impossible to cut specimens ofv uniform' thickness.

An object of the invention therefore, is to construct amicrotome having a.-kni'l'eI carriage so designed andmounted as to prevent the same from being displaced or moved yout of contact with its guide When cutting speci-- mens; valso to construct a knife carriage. and

guide therefor such that the carriage may be held accurately to and be moved `smoothly and easily in a true plane or path; also to provide improved adjustable guide means for such carriages which enables close and uniform contact to be had between the bearing surfaces of said carriage and guide.

' ln some microtomes of this kind in which the knife, blade, is comparatively long, the knife holder included one or more adjustable clamps havin the form of a straight razor like ing apair of jaws embracing the opposite vfaces of the knife. Vhen only one clamp is used this clamp usually` engages the knife near the middle, thus leaving only a relatively .short ,portion of Ethe blade vunobstructedv and available for cutting7 or When the clamp` engages the knife' near one end, the distal end of the knife is unsupported. ln such cases the knife isapt to yield or flex in use and does not cut uniform specimens. On the other hand if the knife is secured in vtivo 'clamps spaced ,apart7 the available cutting portion ofthe knife is restricted to a relatively short intermediate portion between the .clamps and care must be exercised to see that the clamps do not strike the object from lwhich the specimens are to be taken.

Other objectsof theinvention areto provide animproved knife holder for microtomes in which the foregoing objections are avoided and `whereby a relatively increased length of the knife is rendered available for cutting'` the specimens; also to construct a vmicrotomeknife'holder Which permits the use o f a relatively. long knife and vWhich is provided with means engaging the distal or outer end of the knife and which means cooperate With a clamp engaging the inner or proximal end or'v portion thereof to hold the knife securely and rigidly `against flexing inuse 'also to provide a knife holder having an adjust-able clamp and means engaging the di stalend of the knife and Which is also y adjustable, so that the knife can be supported in or disposed at different inclinations relative to the object; also to provide adjustable means including a part engageable with the distal end of the knife and Which part is vformed ,so as not to'project into the face planes ofthe knife thereby permitting substantially all of the knife outwardly beyond said clamp kto be unobstructed and available for cutting the specimens; and also to provide means of this sort which are adjustable so as to cooperate with the holder clamp for mounting knives of different lengths.

lVhen certain objects or substances such as tissues and other anatomical subjects are prepared for cutting into specimens on the microtome by the infiltration of celloidin or the like into the intracellular structure of the object, it has been found that the latter is rendered more or less elastic or yielding and is apt to flex when the microtome knife enters the object,` and thus prevent the cutting of uniform slices or specimens. On the other hand with objects of this kind prepared in paratlin wax and the like, the` resulting block is usually sufficiently rigid or stiff for the purpose.

Further objects of the invention are toconstruct a inicrotoine having improved means for mounting and supporting -the objects to be cut, especially when prepared in celloidin, whereby the objects are rigidly supported and prevented from ieXing When engaged by the knife; also=to provide means of this sort which permits the `specimen block to be surrounded by on embedded iii/paraflin wax or the like substance to render the ob-v ject niore rigid and resistant to .lateral flexing vor displacement; also to provide means which extend about'the object inengagement withthe -sides thereof to rigidly support the same; also lto provide means of this sort in 'the form of a continuous Wall or shell eX- tending about the object and which is constructed to permit successive portions of the latter to beexposed andproject intothe cutable Land which may be formedof separately removableV sections for the llast mentioned purpose; and also to provide 'means of this sort which maybe applied to' or associated with the usual object support or plate so'that an object or prepared block may :be mounted on said support land the space between the same and said supporting means .filled with paralin wax 'or the like Vto act vas a support or 'block of lrela-tively large cross sectional area, and which is of rigid character such that it permits the slices or specimens to be readily cut While offering a maximum resistance to lateral ieXing during such operation;

Other objects are to improve microtomes in the yother respects hereinafter set forth and claimed.

Figure l is a front elevation of a niicrotome showing an embodiment of my invention.

Figure '2 is a vertical, 'sectional view of two sections of the'supportingor reinforcing wall of the object holder. j

Figure 8 is a fragmentary` horizontal section of the securing means'for' one of the sections, on an enlarged scale.

Figure 4 is a plan view of the microtome.

Figure 5 is van elevation, on an enlarged scale, of one end of the lknife holder thereof.

Figure `G is a fragmentary, horizontalsection of a part of the knife holder' on linetS-G Figure l5. Y

Figure 7 is a horizontal sectional view of the knife holder clamp.

'Figure 8 is a transverse, Vertical section of the microtome, approximately on line 8-8 Figure 4, on an enlarged scale.

Figure 9 is a fragmentary, longitudinal section of the knife holder carriage, on line 9-'9 Figure 4, on an enlarged scale.

The microtonie illustrated in the drawings includes a stationary frame A comprising a base 10 and an upwardly extending longi tudinal standard, web or wall 1l. At the frontof the standard ll is arranged the object holder B which is movable and adjustable vertically by suitable feed means to advance the object toward the cutting plane of a knife C. The knife vis horizontally supported in a. knife holder D stationarily mounted upon a knife block or carrier cai'- ri age. E which is adapted to'reciprocate longitudinally on the frame A so as to engage the knife C `with the object to cut the slices or specimens therefrom. Y

` The object holder B, except as'liereinafter ilescribed, is of usual construction comprising a segmental spherical block 12 'which carries an obj ect-plate or support 13 which is grooved on its face for the attachment thereto of one end of the object so that the object projects Y upwardlytherefrom. The block l2 is adjust- 'ably securedV in a socket 14 by 'a plurality of screw actuated jaws l5 which permits the block 12 andthe object to be oriented as a unit to any desired relation to the knife, and firmly secured in adjusted position. The object holder B is carried by a vertically adjustable slide 16 moving in parallel guideways 17 on the standard 1l. Vertical step by step movements are imparted tothe slide for advancing the object intermittently to the knife by a rotatable feed screw 19, having a fine thread and which is actuated by Va ratchet wheel Q20 and -pawl 21, under the control of a hand lever 22. The feed screw 19 raises the object by means of the nut' 19m bearing against-the under side'of support 14 and suit ably held against rotation. A quick return or lowering of` the screw and object holder is effected by a crank 23 through bevel Ypinions 2eand gears The upward step by step movement of the object holder is normally effected automatically through a swinging karm 26 mounted on the recijirocatory knife carriage E, land which has at its lower end a pawl 27 which engages an arm 28 operatively connected to one of the pinions 2d. Each time the carriage E is returned after being actuated to pass the knife C through the object, the

kpawl 27 strikes and swings the arm 28 and causes the desired rotation of the feed screw 19.

In Figure 8 the object or substance from which the slices or specimens aie to :be taken is `represented at ai, being preferably one treated in celloidin to form a celloidin block ofthe usual kind, indicated at m. This block a is in turn, in accordance with the meseta invention, surrounded by a hardened mass of suitable substance, such as paraffin wax m2, of substantial area which acts to stien the otherwise somewhat yielding or flexible block receptacle. The wax or substance in melted form is introduced into the space between said object and said wall or supporting means or cup and allowed to harden. In this way the object is firmly embedded in the wax or substance 0:2, which forms an integral rigid block of relativelylarge cross section, which is further reinforced or supported by the surrounding wall. This wall or support caribe of any suitable character and construction adapted to be adjusted orotlierwise arranged to permit successive poitions'of the completed block or object X tobe moi/'ed into the cutting plane for cutting the slices.

In the particular construction shown an annular wall or shell v30 is employed, which` comprisesa plurality of separate detachablerings or sections 31 interconnectedto each other to form a cylinder like member or shell which, in turn, is detachablyconnectedto the object plate 13. Each of the sections or rings 3l is formed of sheet metal'bent to circular form split lengthwise and with the split edges 32 in abutting relation. The top and bottom ends or edges 34tand 35 of each vsection is indented, grooved or otherwise formed, so that an end of one section canbe engaged with and yconnected to an end of another section, andfirmly secured in this position by any suitable means.

In the construction shown for this purpose the edges 32 of each section is provided with pairs of oll'set tabs or projections 36, the ei;- treme outer Aedges of which are offset Vin opposite directions, and a bolt 3S, extending transversely vof thesplit or joint, with its head engaging one pairof lugs 36, is received in a threaded sleeve or clamp member 39, which when tightened upon the threads ofthe bolt 38, bears against the other pair of projections 36 and acts to draw opposite pairs of projections `on each section toward each other until 'f the edges 32 of the section engage. 1n this manner the several sections or rings are closed l and at the same time the intertitting ends are rigidly clamped one to the other.

The periphery of the supporting plate 13 is formed with an annular groove 40, for the reception of the end of one of the rings or sections 31,' so that a group of sections can be secured thereto so as to lextend upwardly therefrom as shown in Figures l and 8.

lVhen the required number of sections 31 have been secured together upon support 13 as shown in Figures landS, the paraiiin waXror other substance, in melted condition, is poured into this receptacle so as to `fill the space between the celloidin block or object and the walls of the sections 31- and allowed to harden. Y f

After this has taken place the uppermost section 3l is removedso as to expose the upper end of the completed block, and the ratchet mechanism actuated so as to bring the upper endof the block intoY the cutting plane.v

The apparatus is `now operated by reciprocating the knife holder carriage E Vseas to pass the knife C across the top of the object or block X to remove a specimen therefrom, and during the retrograde movement of the carriage E, the ratchet mechanism is actuated so that the feed screw 19 will advance or elevate the object holder B and position said object so to enable another sliceito be taken therefron'i by repeating the described movement of the knife; holder carriage E.

After the major portion of the exposed end of the block or object has been cut away in this -manner anadditional amount or portion of the upper end of said block can be exposedy to the cutting operation by removing another of they sections 3l, which is' effected by unscrewing the sleeve 39 of that vsection so as to permit the ends ofthe'section to separate sufficiently to disconnect the grooved lower end thereof from the corresponding grooved end of the section below.

Preferably, the exposed portion Vof the block X is'pared away to'tapered form as shownin Figures l and t to reduce the area or size of the slice. 1 Il f By the construction and arrangement of the separable annular structure described, the somewhat resilient or yielding celloidin block a is amply reinforced bv the interpositi on of the hard wax between the same and said annular/wall or' structure. Nevertheless successive portions of the block or object can he exposed as required to the cutting action of the knife. By this arrangement also a relatively long block or object canbe prepared and out into a correspondingly large nun'iber of specimens with each single attaching operation.

rin important result attained by the foregoing is that the entire structure consisting of the support parts 12 and 13 and the sections 31 connected thereto, can be oriented as a single unit together with the object X arried thereby. i

ln accordance with the invention the knife holder carriage E is so mounted that during its operative movements it is positively prevented from liftingv or jumping from the guide when the knife yC entersthe obect or block. For this purpose said carriage is constructed in the yform of a substantiallv rectangular Vblock/t2 which is providedl with a longitudinal downwardly openin'grecess le CU 43'on its `under iside closed in part by a pair of opposed fixed bearing plates 44. These plates-44 are provided, within the recess 43,-

with upper bearing` surfaces 45, and their lower faces form bearing surfaces 46. These bearing faces 45 and 46 extend parallel one with theotherin horizontal planes lengthwise of the carriage E. lThe uppei` face of the standard v11 of the frame A is finished or planed to provide parallel, horizontal bearing surfaces 47 against which the lower bearing faces 46 of the .knife carriage E having slidingV Contact. Secured to and extending lengthwise'of said standard l1 and'disposed between said plates 44, is a longitudinal bar 48, to the top face of which is rigidly secured a guide plate 49. This guide plate is adapted to pass through the recess 43 and has formed thereon a pair of spaced longitudinal guide faces 5l slidably engaging the upper bearing faces 45 0f the carriage E. The guide plate or bar 49 is constructed so that its bearing faces may be adjusted towards or from Lthe faces 45, so that a smooth and exact contact may be had between the carriage E and its guide and upward movement or displacef ment of the carriage prevented. For Vthis purpose the plate 49 isldivided lengthwise at each'side thereof by longitudinal, horizontally disposed slits or `grooves 54 providing a pair of opposed laterally extending and relatively rigid upperportions 55 and a pair of corresponding, somewhat yielding lower portions '56. The bearing surfaces 5l are formed on the parts 56. As shownin Figures 4 and 9, the upper portions 55 of the guide bar 49 are provided with a plural-ityhof screws 57 which turn freely in holes in said plate with their lower ends operatively engaging in threaded holes 58 in theloweryielding portionsv56 of the plate so that by turningthese screws inone direction or 'the other the relatively yielding portion 56 of the plate can be vdrawn toward or moved away from the upper portion 55 thereof. A second series of screws 59 having` threaded engagement in holes in the plate parts 55 extend with their lower ends bearing against the upper face of the lower portions 56.` These screws can be turned so as to force the lower portion of the plate away from the upper portion thereof to a limited extent, so that by appropriate adjustments of the screws 57 and 5'9 .the bearing-faces 5l can be placed into accurate relation to the carriage bearing faces 45, in a manner to effect an exact sliding t .for the carriage between the opposed guide faces 45 and 47. v

.By this construction a very accurate, smooth and easy running adjustment or fit may be obtained between the knife carriage E and its guide, 'so 'that the carriage may move at all times in a direct plane Ywhile being prevented "from 'displacement Vwhen lthe knife C engages a relatively Atough object on the specimen holder;

The knife holder D before mentioned, with the exception of certain parts to be described, may be of any suitable construction Vadapting it to .support the knife C vina horizontal plane in angular relation to the object oii the object holder B. In the construction shown the knife holder yD comprises an attachingr portion-or block 60 having a flat. 'lower bearing face 61, which rests upon the plane top face of thev knife holder carriage E. The knife holder can be adjustably secured on the carriage E by any suitable means, such as a .pair of clamping screws 62, the heads of which engage in T shaped longitudinal slotsI 63 formed in the top face of the carriage or slide E. The threaded portions of the screws 62 extend upwardly through transverse slots 64 in the block 60, and are received in hand nuts or clamp members 65 which, when tightened, bear on the top of the block 60 and draw the screw heads up'tiglitly in their slots. Thus the knife holder can be adjusted and rigidly secured at any desired angle in a horizontal plane with reference to the knife can vriaofe E.

'xtending 'forwardlylfrom the block 60'is a suitable knife clamp which includes a fixed upper jaw 7l formed integral with the block 60, andan adjustable lower'j a'w 72. The

jaws 7l and 72 are adaptedto straddle the back of the knife'C preferably near its inner end so as to extend for a distance over the upper and lower 4fac'esof the knife. The lowico er aw 72 vis mounted on a yhorizontal pivot 74 extending through, and between a pair of .fixed lugs 75 on the knife holder, -and an adjusting screw 76, passing downward-ly through 'the upper'fixed jaw and bearing upon f the lowermovable jaw 'rearwardly of its'pivot -so that the Yknife may be tilted to position its cutting edge indifferent planes, After the lower jaw has been adjusted, a pair of clamping Yscrews 77 also passing through the fixed upper'j aw are rotated so that'thei-r lower ends" engaged `the top'face of the knife C, thereby forcing it firmly against the lower jaw 37s.

vThis clamp 70 is also provided with a pair of transverse screws 78,the ends of which bear against the back edge of knife .C for adj usting the knife ina transverse direction.

Extending laterally from the -block VC of lthe knife holder D, is a supporting arm or member 8O which is provided with means at its outer or free end for engaging and sup# porting the Youter or distal end'of the k-nife C. These means are'also adjustable. as-to cooperate with clamp 70 for *positioning .the knife in different planes in accordance material to be cut.

In the construction shown the arm 8O of the knife holder is slotted lengthwise at 8l for the reception of clamp device or screw v382 whichlpasses through lsaid Aslot 812 with its with the' Y therefrom about said object and which comand said means permitting the sections to be released vand disconnected one after another to expose successive portions of said object for cutting slices therefrom.

8.l A niicrotome having an object holder comprising a support to which an object is attached, and a bracing member extending therefrom about said object a-nd which comprises plurality of longitudinally split inein-y bers having interfittmg parts for connecting o them together end toend, means for drawing the severed portions of said sections together, and which means simultaneously causes said iiiterfitting parts of adjacentsections to rigidly inteiglockyand saidineans being adjustvablevto release said sectionsone after another to expose. successive portions of said object for cutting slices therefrom.

9, An object holder for a niicrotome including a support for the object, and a plurality of sections each comprising an annular wall Vhaving its opposite endsformed to detachably interfit with the ends of other sections Whereby a continuous Wall; adapted to surroundsaid object mayA be formed by connecting said sections end Ato end, and means for detacha-bly and securely retaining said sections4 in connected relation, and which means also permits said' sections to be detached one after another to expose successive portions of saidobject. y

l0. An object holder for a niicrotome including a: support for the object, and a plu rality of sections each comprising an annular wall split lengthwise and the severed edgesofj which are adaptedto abutand each having its opposite ends formed to interlit with the ends of other sections, whereby a continuous wall yadaptedto surround said object may be formed' by connecting said sections end to end, means for holding the abutting edges of said sections in contact and for Y securingsaid sections rigidly together, and

'whichmeans also permits said-sections to be Y detached one after another to expose succes- SOY sive portions of said object.

1l. An object holder for av inicrotoiiie, in-

,f cluding a; support for theoloject,` and afplurality ofsectionseach comprising an annu-- lar Wall ofA sheet, metal, split lengthwise and the severed ends of Ywhich are normally separated and which may be brought into abutting relation by flexing said section, securing means on each section for holding said abutting edges together, and said sections having iiiterfitting parts permitting said sections to vsuiiouiid said object may be formed by connecting said sections end to end, and Vsaid support also having a part formed to interi'it with an endv of one of said'sections, so that said connected sections may be mounted thereon, and means detacliably and securely retaining said sections and said support in connected relation, and which means also permits saidl sections to be removed' one after another to expose successive portions of said object.

1B. vAn object holder for a inicrot-ome including a member on Which said object is supported, apart on which said member is mounted by a ball and socket connection, and a rigidbracing member comprising a pluralityr of sections detachably connected end to end and one of which is detacliably con. .Y

nected to said object support, whereby successive portions of said object may be exposed by detaching one after another of said sections, and-saidball and socketconnection permitting said object, said support and saidv` sectional bracing member to be oriented as a unit to different positions so that specimens may be cut from the exposed portions of said objectV Y lt. A microtoine having a sup-port for an object, a knife,`a carriage on which said knife is rigidly mounted and which is yreciprocable for engaging said knife with said object to cut specimens therefrom, said carriage having a substantially horizontal bearing face, a frame having a complementary bearing face on which saidicarriage face .slidably engages,

Y and means onsaid frame engaging said carriage to maintain positive engagement of said carriage bearing face with said frame bearing. v face in thereciprocatory movements of said carriage. Y

l5. A niicrotome having a support for an object, a knife, a carriage on which said knife is rigidly mounted and which is reciprocablan for engaging said knife with said object to cut specimens therefrom, said carriage having opposed bearing faces, a frame having a bearw ing facelwivth which one of said carriage bearing faces engages, and a partfxed on saidi frame Vand engaging said other carriage bearing face, I hearing v said frame nearing face@- fixed part disposed ing face, Wliereliy said arriage ispositivel'y maintained insliding contact with eaidframe in its'reoiproo'atory movements. y

1 6.V Al mic-retorno .having a support for an object. a lf'nife, a carriage enwhich .said knife is rigidly mounted" and which ie eciprocable for enga ingfsaid knife with said objet-t to ont Specimens therefrom, Asaid. carriage rhaving opposed beni-ined faces, a frame having ahearin" face with which one of said carriage hearc j D Y ing faces engages, and a part fined on said lframe engaging said other carriage bearing for engaging said knifervith said object lo cut 'specimengesfthere om, a frarne'having a bear- -'nnl s aid carriage having oppossed` yin spaced relation to saidfr'ame ,bearingj face and having a 4face complementary tothe latter and which slidably vengagessaid 'other car-y riageheariiig face,v whereby said carriage is positiiely maintained in sliding engagement With said frame in its reeiprocatory movements.

18. A inicrotoine having a support for an oh]eet, a knife, a carriage on which said. knife is rigidly mounted and which is reciprocable for engaging said. knife with said'obg ect to cut specimens therefrom, said carriage having a laterally extending part formed with rippen and lower parallel hearing faces, and a frame having complen'ientary upper and lower parallel bearing faces engaging said carriage hearing faces for guiding and maintaining said carriage in positive relation to said frame in its reeiproeatory movements.

19. A inicrotoine having a support for an'r object, a knife, a carriage on which said knife is rigidly mounted and which is reciproeable for engaging said knife with said'oloject to cnt specimens therefrom, said carriage having a laterally extending part formed with upper and lower parallel bearing faces, and a frame having a lower bearing face upon Which the corresponding face of said carriage sli-dablyengages, and a bar on said frame overhanging said laterally extendingpart of said carriage and having a bearing face engaging downwardly upon said upper bearing face of the latter to positively hold said carriage against Said frame bearing face in its reciprocatoryv movements.

20. A microtonie having a support for an object, a knife, a carriage on which smidknife. l is rigidly mounted and which is reciprocalole for engaging said knife with said object to cut i ofA said yface -rvitli y fated for menging Said knife with said object f ohstructingthe same;

tioned: in different-relations to' said object;

adjustments of salidQclam L cated for engaging saidr'knife .with said oh-` `)ect to cut fspecimens" therefrom, and clamp instable to permit ,forY accommodating gknives" of jdiierent "Oli specimens tlierefron'l, said carriage having a laterally extending part formed with upper and'linver parallel hearing faces, and a frame having lower-hearing face'upen which the oornesigion,dn'igV face of saidcarriage slidahlya70 engages, and bar on said frame overhanging Asaid laterally extending part of said carriage andhaving a hearing face engaging doWnwardly upon said upper bearing face of the latterto positively hold said carriage against a -7 5 .r v r i'" said iraine bearing face in its reciproeatory n'1oveinents,'and said bearing face of saidvbar being formed on a part thereof which is adji'is'tahle to effect preciseand uniform Contact the fadjaeent bearing facee` of Said'carriagekl-'rmicrotoine having a support forV an einem, a straight knife, and a helder for said knife which is mounted so as to he recipro- :ya t. to cut'l specimens therefrom, a `clamp` firmly engaging Aopposite faces of said knife adjacent one end thereof, and a part cai: ied bv said knife. holder Whiclriirinly engages and supports the distal end of said knife :vit-houle 22. A' inicrotome having a support for an obiect, straight knife,v and a'r`liolder vfor" 'i saidkni'fe which ismou'nted 'so as to be reciprocate'd for engaging-saidknife'ivith said` objectto cut specimens therefrom, and a clamp firmly'engaging oppositerfaces o fsaicl lnnfeadjacent one end'thereof and which is adjustable to permit;V said knife tohe posifand'a part carried by `sai d h'older'which firmly 'engages and supportsy thedistal endl of said knife Without obstructing the latter, and ivlnch part ieradjustahle todiiferent positions relative` to said holder Lto-coirespond with the g asupport .for an y 23. A microtoine havi gohject, a straiglitknife, and aholder for'said lmifefvi'fhich is mountedfso Aas: to `he reciproosite faces of? sai-d knife thereof, and which is aderefi @eee-eraan adjacent one en'l Raid knife 'to be 'adjuetelil about and also transversely'of its'lonegifadinal axis to poSitioii it in different relations to said object, and 'a part carried lov-saidv knife holder which firmly engagesiand snpportsthe distal end of said knife and iv ih is also adjustable 'about :and transversely of eaidi'axis of said knife to "correspond vvith the adjnstmentsof said clamp, and said part heingalso adjustablelengthivise of said aXis lengtlisL f Y Y 'Y 125 2 .Agmficrotonie having a Support for an I al straight knife liavingloppo'siefconf vergnng,facesy Ateiniiiating in "a `ciittinigE edee ana knife.liolderupen vvhifch'f said kni'fehis secured andivhichifis "reiprocahly mounted k for engaging said knife with said object to cut specimens therefrom, and a.V member on said1 holder havinga projecting part Which firmly engages the distal end of said knife and which is disposedA between-the planes of saidl knife facesA so as not to obstruct the latter.

. 25. A microtome having a support for an object, a straight knife having opposite converging faces terminating in a cutting edge,`

itsv longitudinal axisin different relations to said, obj ect.Y

2G. A microtome having al support for an object, a straight knife having a transverse end Wall and a seat formed therein,l and a knife holderruponwhichsaidknife is secured and which) is; reciproca-bly mounted for en-` gaging said` knife with said object to out specimens. therefrom, a member on said holder having a stud extending parallel `With the longitudinalaxisof said knifeand which is adapted to engage insaid seat in said Wall thereof, vvhe reby said knife may bev turned on said studand adjustedjabout said axis in different. relations to said object, and means rigidly securing said member and said knife in adjusted positions.

27'. A microtome having a support` for an obj ect, a straight knife, anda holder` for said knife which is mounted so as to be reciprocated for engaging said knife with saidobject toY out specimens. therefrom, securing means on said holder engaging said knife J adjacent one endthreof, an arm extending laterally from:K said holder, and a. part adjustably mounted on the free end of saidarm for movement, relatively theretotoward said securing means. for engaging and. supporting the distal endv of4 said knife.

'28. A' microtome having. aY support for anv object. a; straight` knife having a. transverse end, wall and a, seat formed therein, a knife holder-upon which said knife issecured and which is reciprooably mounted for engaging` saidirknife-With said object to cut specimens.

therefrom,x adjustable securingmeans on said holder for .engaging andv supporting said knife adjacent one. end thereof, an arm eX- tending laterallyr from said holder, a member -adjustablv meunted thereon for movementfparallelfwith the longitudinal axisf Said-,Ignite and apart Cerfd by Said 1Q-mwhich. is adjustable transversely lof* said Y axis-and relativel'v 4tosaid member and. whieh operatively engages and supports the-distal end of said knife, means for securing said member on said arm and means for clamping said part against said member and said knife* 29. A microtomehaving a support for an object, a straight knife having a transverse end Wall and a seat formed therein, a knife holder upon Which'said knife is secured and which is reciprocably mountedk for engaging said knife With said object to cut specimens therefrom, adjustable securing means on said'l holder for engaging and supporting said knife adjacent one end thereof, an arm ex tending laterally from said holder, a knife supporting member having a part formed to bear against said arm and a part engageable for forcing said member firmly against said arm and said knife. I

30. In a microtome,va knife having opposite converging faces terminating in a cutting edge and having a transverse en d Wall, and a holder for saidknife comprising-clamping means'engaging said opposite faces thereof ata distance from said end Wall thereof, and means extending between the planes of said knifefaces-and bearing againstfsaid end' Wall thereof; for supporting that end of the knife Without obstructing said faces.

HARVEY N. OTT.

With the distalend ofsaid knife, and means 

